A FEW THOUGHTS ABOUT FLUIDS IN KIDS William Primack, MD UNC Kidney Center Chapel Hill NC USA August 21, 2006

HOMEOSTASIS The living organism does not really exist in the milieu exteriour (the atmosphere it breathes, salt or fresh water if that is its element) but in the liquid milieu interior formed by the circulating organic liquid which surrounds and bathes all the tissue elements, this is the lymph or plasma, the liquid part of the blood which in the higher animals is diffused through the tissues and forms the ensemble of the intercellular liquids which is the basis of all local nutrition and the common factor of all elementary exchanges. The stability of the milieu interior is the primary condition for the freedom and independence of existence, the mechanism which allows of this is that which ensures in the milieu interior the maintenance of all the conditions necessary to the life of the elements. Claude Bernard

Body spaces

Body spaces by age

Maintenance fluids Holliday M and Segar W –Pediatrics 1957;19: kcal~100ml Their data led to the 100:50:20 protocol for the AVERAGE hospital patient

Maintenance fluids Holliday M and Segar W –Pediatrics 1957;19: kcal~100ml Their data led to the 100:50:20 protocol for the AVERAGE hospital patient We never admit any kids like that!!!

MAINTENANCE FLUIDS What makes up 100 ml/kg Water (ml/100 kcal) Respiratory40-50 Sweat0-5 Urine50-75 Stool water5-10 ‘Hidden intake’ Water of oxidation (10-15) Totals

MAINTENANCE FLUIDS Abnormal losses Water (ml/100 kcal) Abnormal losses Range (ml/kg) Respiratory Sweat urine Stool water ‘Hidden intake’ Water of oxidation (10-15) Totals

Maintenance fluids Adjustments to 100:50:20 rule Increase maintenance fluids –By 12 % for each degree C of fever –Insensible losses from 45 to ml/100cal for hyperventilation Decrease maintenance fluids –Insensible losses from 45 to 0-15 ml/100cal for high humidity (= ventilator)

Maintenance fluids Unless you know what you are replacing and why, using maintenance plus (e.g. 1 ½ x maintenance) is illogical

Maintenance fluids An alternative approach Based on body surface area Use estimated insensible losses and replace all other fluid losses based on volume and content Recalculate as often as needed q6h-q24h Probably more accurate for PICU type patients

BODY SURFACE AREA BSA (M2) of average proportioned Newborn= kg infant = kg child = kg adult = 1.73 If average proportioned 3-30 kg BSA=(wt + 4)/30

MAINTENANCE FLUIDS Daily water requirement Water (ml/100 kcal) Water looses per M2 BSA Respiratory Sweat urine Stool water ‘Hidden intake’ Water of oxidation (10-15)(150) Totals

Continuing losses NO MATTER WHICH SYSTEM YOU USE It is essential to regularly reassess child for continuing losses. Regularly reevaluate effectiveness of your fluid prescription and modify it p.r.n. May need to recheck labs more than q.d. Reweigh more than q.d. if appropriate

Contents of abnormal losses meq/liter FluidNaKClHCO3 gastric pancreatic small bowel bile ileostomy diarrhea

Comparison of Electrolyte Composition of Diarrhea Caused by Different Organisms Etiology Electrolytes (mMol/L) mOsmols Na+K+ClHCo 3 Cholera Rotavirus ETEC Molla et al. J Pediatr 1981; 98: 835

MAINTENANCE FLUIDS Fluids based on BSA Water (ml/100 kcal) Water (ml/M2) Na MEQ/M2 K MEQ/M2 Insensible loss Sweat urine Stool water ‘Hidden intake’ (10-15)(150)00 Totals

Case 1 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 24 hours On exam decreased turgor, dry mouth, BP 90/60, wt= 9 kg. Labs Na=140, K=4, HCO3=17, BUN=30, creatinine=0.4. Receives ml/kg bolus and makes some urine

Isotonic dehydration

Isotonic dehydration correction waterNaKHCO3 maint deficit

Isotonic dehydration correction waterNaKHCO3 maint deficit total ½ in first 8 hrs, remainder over 16 hours Reassess for and replace continuing losses

Case 2 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 24 hours Given ‘clear fluids’. On exam decreased turgor, dry mouth, BP 80/50, wt= 9 kg. Labs Na=125, K=4, HCO3=15, BUN=40, creatinine=0.4. Receives ml/kg bolus and makes some urine

Hypotonic dehydration

Hypotonic dehydration correction waterNaKHCO3 maint deficit

Hypotonic dehydration correction (Desired Na – measured Na) X TBW (135 – 125) meq/l X.6 l/kg = 6 meq/kg Thus deficit= 60 meq Na

Hypotonic dehydration correction waterNaKHCO3 maint deficit total ½ in first 8 hrs, remainder over 16 hours Reassess for and replace continuing losses

Case 3 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 48 hours Continues to drink cow’s milk On exam nl to ‘woody’ turgor, moist mouth, BP 90/50, wt= 9 kg. Labs Na=170, K=4, HCO3=18, BUN=25, creatinine=0.4. Receives ml/kg bolus and makes some urine

Hypertonic dehydration

Hypertonic dehydration correction waterNaKHCO3 maint deficit1000 total Lower maintenance water requirement as high ADH will decrease UO

Hypertonic dehydration initial day correction waterNaKHCO3 maint deficit = total Target is to drop Na by 10 meq/day. Lower maintenance requirement as high ADH will decrease UO Reassess for and replace continuing losses

Hypertonic dehydration correction Lower maintanence requirment as high ADH will decease UO Goal is to decrese Na by 10 meq/day (Desired Na – measured Na) X TBW (165 – 175) meq/l X.6 l/kg = 6 meq/kg Thus sodium surplus= 60 meq Na

Comparison of Effect of Glucose on Net Stool Rate with Galactose and Fructose in Perfusions Delivered Uniformly throughout Most of the Small Intestine via Multilumen Tube 12-HOUR PERIODS Pre-perfusion Perfusion with electrolytes and 61 mM galactose Perfusion with electrolytes and 56 mM fructose Perfusion with electrolytes and 58 mM glucose Perfusion with electrolytes only Post-perfusion MEAN NET STOOL OUTPUT RATE (ml/hr) Adapted from Hirschhorn N et al. N Engl J Med 1968; 176

Na-glucose co-transport Intestinal brush border Duggan C JAMA 2004;291:2628

Outcome of Oral Treatment of 216 Patients with Rotavirus Initial TreatmentSuccessFailure* Oral (n = 197)188 (95)9 (5) Intravenous (n = 19)17 (89)2 (11) Total (n = 206)205 (95)11 (5) *Requiring unscheduled treatment intravenously. Percentages are given in parentheses. Taylor PR et al. Arch Dis Child 1980; 55(5):

Spandorfer et al.Pediatrics 115 (2): 295. (2005 ) ORAL vs IV REHYDRATION IN MODERATE DEHYDRATION

ORS ml/kg over 3-4 hours of ORS If vomiting give in sips (Pedialyte pops) May also add 5-10 ml/kg per diarrheal stool for ongoing losses Expect increased stool content After rehydration, CHO rich foods Continue nursing

ORS and other ‘clear liquids’ CHO g/l Na Meq/l K Meq/l Cl Meq/l base Meq/l mOsm/ kgH20 Pedialyte WHO ORS Gatorade Apple juice Coca cola OJ